NAME
Gentoo::ChangeLog::Parser::Eventual - Rudimentary Event-Based ChangeLog
format parser, inspired by Pod::Eventual.
VERSION
version 0.1.2
SYNOPSIS
use Gentoo::ChangeLog::Parser::Eventual
my $parser = Gentoo::ChangeLog::Parser::Eventual->new(
callback => sub {
my ( $parser, $event, $opts ) = @_ ;
},
);
$parser->handle_line( "This is a line", { key => 'value', line => 1 });
DESCRIPTION
In the proceeds of making a ChangeLog parser, I kept getting stuck on
various parts with writing it cleanly.
This design, inspired by RJBS' Great "Pod::Eventual", greatly simplifies
the process by using very rudimentary and loose data validation.
Lines are fed in manually, because we didn't want to implement all the
File IO our self and didn't want to limit the interface by forcing
passing a file handle.
You can do the IO quite simply anyway.
while( my $line = ){
chomp $line;
$parser->handle_line( $line , { line => $. } );
}
A parser instance has a bit of state persistence, so you should use only
1 parser per input file.
Currently, it can only detect a few basic things.
1. Header blocks.
We go naive and classify that entire "# ChangeLog for " section at
the top of a ChangeLog as a "Header".
The header itself is not validated or parsed in any way beyond the
notion that its a series of comments.
2. Release statements.
Raises an event when it sees
*perl-5.12.2 (10 Jun 2010)
3. Change Headers.
This is the part on the top of each ChangeLog entry as follows:
10 Jun 2010; Bob Smith :
There are multiple ways this can be done however, so there are 3
events for this.
4. Change bodies.
This is the part after the header.
5. Blank Lines.
METHODS
handle_line
handle_line is the only public method on this object. It takes one line,
processes its own state a bit, works out what event(s) need to be
thrown, and call the passed callback.
Specification: $object->handle_line( Str $line, HashRef $opts )
Parameter: $line : Mandatory, Str
This must be a string, and this is the string that represents a singular
line from the ChangeLog to be parsed. This code is written under the
assumption that you have also pre-chomped all your lines, but doesn't
enforce it. However, its not guaranteed to work, and is not tested for,
and may in a future revision be enforced.
Parameter: $opts : Mandatory, HashRef
This is a HashRef of data to be sent through to the event handler.
This is a good place to specify the source line number of the line you
are currently parsing if you want that.
$object->handle_line("this line", { line => 4 } );
and then in the callback:
my( $parser, $event, $opts ) = @_ ;
print $opts->{line} = 4;
ATTRIBUTES
_callback
Outside construction and providing this (required) attribute, no public
methods exist for working with it.
Specification: CodeRef, rw, required, init_arg => callback
Construction.
my $object = ::Elemental->new( callback => sub {
my( $parser, $event, $opts ) = @_ ;
.... event handler code here ....
});
Parameter: $event : Str
This is the name of the event that has been triggered. See "EVENTS".
Parameter: $opts : HashRef
This is a Hash Reference of data about the event. Mostly, it contains
whatever data was passed from "handle_line", but it injects its own
'content' key containing a copy of the string that was parsed.
Executing.
You can manually execute the CodeRef as if it were called internally,
but there is little point to this.
$object->handle_event( 'an-event-name' => { } );
Note, that the event-names list is baked into this class, and manually
calling this method and passing an unsupported event name will result in
casualties.
EVENTS
start
Fires when the first line is parsed.
blank
Fires on blank ( i.e.: all white space ) lines.
header
Fires on the first header line.
header_comment
Fires on all comments that are deemed "part of the header"
header_end
Fires on the first line that is obviously not part of the header,
terminating the header.
release_line
Fires on "*perl-5.12.2" lines.
change_header
Fires on Single-line change headers.
change_body
Fires on each line that looks like it was a child of the previous change
header.
end_change_body
Fires when the first line is seen that indicates the change body is
complete.
begin_change_header
Fires on the first line of a multi-line change header.
continue_change_header
Fires on all non-blank lines in a multi-line change header other than
the first and last.
end_change_header
Fires on the last line of a multi-line change header
UNKNOWN
Fires in the event no processing rules indicated a success state.
AUTHOR
Kent Fredric
COPYRIGHT AND LICENSE
This software is copyright (c) 2013 by Kent Fredric .
This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.